Abstract: The present disclosure relates to an iron-based prealloy powder having excellent strength and processability, and an iron-based alloy powder for powder metallurgy and a sinter-forged member using the same. The iron-based prealloy powder for powder metallurgy according to an embodiment of the present disclosure includes 0.5 to 5.0 wt % of Cu, 0.1 to 0.5 wt % of Mo, and a balance of Fe and other inevitable impurities. A Cu content (Cu %) and a Mo content (Mo %) satisfy the following Relational Equation (1): 0.3×Cu %+3×Mo %?2.7??(1).

Abstract: The present disclosure relates to an iron-based prealloy powder having excellent strength and processability, and an iron-based alloy powder for powder metallurgy and a sinter-forged member using the same. The iron-based prealloy powder for powder metallurgy according to an embodiment of the present disclosure includes 0.5 to 5.0 wt % of Cu, 0.1 to 0.5 wt % of Mo, and a balance of Fe and other inevitable impurities. A Cu content (Cu %) and a Mo content (Mo %) satisfy the following Relational Equation (1): 0.3×Cu %+3×Mo %?2.7??(1).

Abstract: The present disclosure relates to an iron-based prealloy powder having excellent strength and processability, and an iron-based alloy powder for powder metallurgy and a sinter-forged member using the same. The iron-based prealloy powder for powder metallurgy according to an embodiment of the present disclosure includes 0.5 to 5.0 wt % of Cu, 0.1 to 0.5 wt % of Mo, and a balance of Fe and other inevitable impurities. A Cu content (Cu %) and a Mo content (Mo %) satisfy the following Relational Equation (1): 0.3×Cu %+3×Mo %?2.7??(1).

Abstract: Provided is an alloy steel powder for powder metallurgy containing an iron-based powder as a main component that is capable of achieving both high strength and high toughness in a sintered body using the same. In the alloy steel powder, the iron-based powder contains a reduced powder, and Mo content with respect to a total amount of the alloy steel powder is 0.2 mass % to 1.5 mass %, Cu powder content with respect to a total amount of the alloy steel powder is 0.5 mass % to 4.0 mass % and graphite powder content with respect to a total amount of the alloy steel powder is 0.1 mass % to 1.0 mass %.

Abstract: An Fe—Mo—Cu—C-based alloy steel powder for powder metallurgy has a chemical composition containing Mo: 0.2 mass % to 1.5 mass %, Cu: 0.5 mass % to 4.0 mass %, and C: 0.1 mass % to 1.0 mass %, with a balance being Fe and incidental impurities, wherein an iron-based powder has a mean particle size of 30 ?m to 120 ?m, and a Cu powder has a mean particle size of 25 ?m or less. Despite the alloy steel powder for powder metallurgy having a chemical composition not containing Ni, a part produced by sintering a press formed part of the powder and further carburizing-quenching-tempering the sintered part has mechanical properties of at least as high tensile strength, toughness, and sintered density as a Ni-added part.

Abstract: A method for measuring an apparent density of a metal powder includes holding a metal powder in a vessel, applying an alternating magnetic flux to the metal powder using an exciting coil disposed outside the vessel, detecting the alternating magnetic flux passed through the metal powder using a-search coil disposed outside the vessel, and determining an apparent density of the metal powder from an amplitude of the detected alternating magnetic flux using a calibration curve representing a correlation between the apparent density of the metal powder and the amplitude of an alternating magnetic flux prepared in advance. The method enables to measure the apparent density of a metal powder with a high precision in an on-line and non-contact manner without stopping a process of producing a mixed powder or a process of producing a powder compact.

Abstract: A method for measuring an apparent density of a metal powder includes holding a metal powder in a vessel, applying an alternating magnetic flux to the metal powder using an exciting coil disposed outside the vessel, detecting the alternating magnetic flux passed through the metal powder using a search coil disposed outside the vessel, and determining an apparent density of the metal powder from an amplitude of the detected alternating magnetic flux using a calibration curve representing a correlation between the apparent density of the metal powder and the amplitude of an alternating magnetic flux prepared in advance. The method enables to measure the apparent density of a metal powder with a high precision in an on-line and non-contact manner without stopping a process of producing a mixed powder or a process of producing a powder compact.

Abstract: A method of producing a mixed powder for powder metallurgy comprises: mixing an iron-based powder with a Mo-containing powder and a Cu-containing powder, to obtain a raw material mixed powder; heat-treating the raw material mixed powder to cause Mo and Cu to diffusionally adhere to a surface of the iron-based powder, to obtain a partially diffusion-alloyed steel powder; and mixing the partially diffusion-alloyed steel powder with a graphite powder, to obtain a mixed powder for powder metallurgy, wherein the iron-based powder has an average particle size of 30 ?m to 120 ?m, a cuprous oxide powder is used as the Cu-containing powder, and the mixed powder for powder metallurgy has a chemical composition containing Mo: 0.2 mass % to 1.5 mass %, Cu: 0.5 mass % to 4.0 mass %, and C: 0.1 mass % to 1.0 mass %, with a balance being Fe and incidental impurities.

Abstract: A finish heat treatment apparatus for an iron powder. Raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In a pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.

Abstract: An Fe—Mo—Cu—C-based alloy steel powder for powder metallurgy has a chemical composition containing Mo: 0.2 mass % to 1.5 mass %, Cu: 0.5 mass % to 4.0 mass %, and C: 0.1 mass % to 1.0 mass %, with a balance being Fe and incidental impurities, wherein an iron-based powder has a mean particle size of 30 ?m to 120 ?m, and a Cu powder has a mean particle size of 25 ?m or less. Despite the alloy steel powder for powder metallurgy having a chemical composition not containing Ni, a part produced by sintering a press formed part of the powder and further carburizing-quenching-tempering the sintered part has mechanical properties of at least as high tensile strength, toughness, and sintered density as a Ni-added part.

Abstract: Provided is an alloy steel powder for powder metallurgy that is capable of achieving both high strength and high toughness in a sintered body using the same. An alloy steel powder for powder metallurgy of this disclosure comprises a composite alloy steel powder and graphite powder. The composite alloy steel powder has a specific surface area of 0.100 m2/g or more and Mo content in a range of 0.2 mass % to 1.5 mass %, and the graphite powder content with respect to 100 mass % of the alloy steel powder for powder metallurgy is in a range of 0.1 mass % to 1.0 mass %.

Abstract: A mixed powder for powder metallurgy includes a machinability improvement powder that is crystalline layered alkaline silicate heat-treated at 400° C. to 1100° C. and whose mix proportion is in an amount of 0.01% to 1.0% by mass in terms of total content of an iron-based powder, an alloying powder, and the machinability improvement powder. Such a mixed powder not only enables a compact to be sintered without adversely affecting the environment in a sintering furnace, but also enables a sintered body having excellent lathe machinability and excellent drill machinability to be obtained.

Abstract: Provided is an alloy steel powder for powder metallurgy containing an iron-based powder as a main component that is capable of achieving both high strength and high toughness in a sintered body using the same. In the alloy steel powder, the iron-based powder contains a reduced powder, and Mo content with respect to a total amount of the alloy steel powder is 0.2 mass % to 1.5 mass %, Cu powder content with respect to a total amount of the alloy steel powder is 0.5 mass % to 4.0 mass % and graphite powder content with respect to a total amount of the alloy steel powder is 0.1 mass % to 1.0 mass %.

Abstract: In a finish heat treatment method and finish heat treatment apparatus for an iron powder, a raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In the pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.

Abstract: In a finish heat treatment method and finish heat treatment apparatus for an iron powder, a raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In the pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.

Abstract: A method for measuring an apparent density of a metal powder includes holding a metal powder in a vessel, applying an alternating magnetic flux to the metal powder using an exciting coil disposed outside the vessel, detecting the alternating magnetic flux passed through the metal powder using a search coil disposed outside the vessel, and determining an apparent density of the metal powder from an amplitude of the detected alternating magnetic flux using a calibration curve representing a correlation between the apparent density of the metal powder and the amplitude of an alternating magnetic flux prepared in advance. The method enables to measure the apparent density of a metal powder with a high precision in an on-line and non-contact manner without stopping a process of producing a mixed powder or a process of producing a powder compact.

Abstract: In a finish heat treatment method and finish heat treatment apparatus for an iron powder, a raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In the pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.

Abstract: High compressibility iron powder that is suitably used for parts with excellent magnetic characteristics or high density sintered parts and that has good productivity is provided from pure iron powder which includes, as impurities in percent by mass, C: 0.005% or less, Si: more than 0.01% and 0.03% or less, Mn: 0.03% or more and 0.07% or less, P: 0.01% or less, S: 0.01% or less, O: 0.10% or less, and N: 0.001% or less, and whose particle includes four or less crystal grains on average and has a micro Vickers hardness (Hv) of 80 or less on average. The circularity of the iron powder is preferably 0.7 or more.

Abstract: A pure iron powder of a diameter of 10 to 500 ?m and a purity of 99% by mass or more is heated to a temperature in the range of 600 to 1400° C., and a Si-concentrated layer is formed in regions within a depth of 5 ?m from the surfaces of the powder particles by gas-phase reaction at a temperature of that range. The average Si concentration in the regions within this depth is controlled in the range of 0.05% to 2% by mass. Thus, a dust core metal powder enhancing the adhesion of insulating material to the particle without degrading compressibility is produced. The resulting dust core maintains a high saturation magnetic flux density and exhibits a low iron loss.

Abstract: This invention provides a metal powder for powder magnetic cores, which have good insulation performance and high magnetic flux density, and which is favorable for motor cores. Ferromagnetic metal powder may be coated with a coating material and a phosphate or phosphoric acid compound containing aluminum is used for the coating material. Coating the surface of iron powder with aluminum phosphate realizes to produce high-quality powder magnetic cores that have good insulation performance and high magnetic flux density and are favorable for motor cores. Further coating the aluminum phosphate-coated metal powder with silane compound or surfactant realizes more stable compressed shaped articles of the powder. And the properties of the articles do not fluctuate while stored for, so long as they are resistant to moisture. This invention contributes to producing powder magnetic cores for motors, and to the process for powder magnetic cores, furthermore, to the related art field.